VulnerabilityDeferred

CVE-2026-68528

Concrete CMS RSS Displayer block below version 9.5.3 rendered remote feed item titles without HTML escaping, resulting in stored cross-site scripting.

MEDIUM 6.0EPSS 0.21%

Does this matter?

Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.

Description

Concrete CMS RSS Displayer block below version 9.5.3 rendered remote feed item titles without HTML escaping, resulting in stored cross-site scripting. An attacker able to control a title in a syndicated feed could execute script in the site origin for any visitor to the affected page, including administrators, without holding an account on that site. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.0 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks riodrwn for reporting.

CVSS 4.0: 6.0 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.21% probability · 11th percentile
CISA KEV: Not listed
Weakness: CWE-79
Source: ff5b8ace-8b95-4078-9743-eac1ca5451de

References

https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.